246 DAVIS — SYSTEMATIC GEOGEAPHY. [Aprils, 



dant experience, of being better able to treat existing land forms 

 by a rational instead of by an empirical method. It is the geolo- 

 gist who studies the past history of the earth ai an end in itself; it 

 is his duty to unravel all the tangled skeins of earth history, how- 

 ever far back they may lead him. The geographer is concerned 

 with the past not as an end but as a means to an end ; and he cares 

 only for so much of it as shall serve his present needs. 



lo. Value of Ideal Geographical Types. — The addition of expla- 

 nation to the responsibilities of the geographer brings with it the 

 need of idealizing actual forms into type forms, for it is chiefly in 

 terms of type forms that actual forms are in fine described. This is 

 also a discouragement to geographers of the more conservative 

 school, who have thought that geography was concerned only with 

 matters of fact, immediately observable. They must however 

 come to see that direct observation is entirely insufficient for the 

 geographer's needs, ^or the simple reason that if he recorded only 

 what he saw he would be overwhelmed with ungeneralized items. 

 He must generalize in order to bring the observable items within 

 the reach of descriptive terms, and as soon as he generalizes, the use 

 of idealized types is practically unavoidable. Such types have long 

 been in current use, but they have been too few and too empirically 

 defined for the best results. They need to be greatly increased in 

 number, and at the same time they must be correlated with struc- 

 ture, process and time ; for only by following the path of nature's 

 progress can we hope to store our minds with types that shall imi- 

 tate nature's products. It may be fairly urged that the larger the 

 store of types a geographer possesses, and the more careful and 

 numerous the comparisons with nature by which the types have 

 been rectified, the better progress can the geographer make in new 

 fields of observation. 



II. Service of Deduction in Geography. — But the geographer 

 who adopts the explanatory methods in a whole-souled fashion will 

 find himself called upon not only to imagine a large series of 

 type forms ; he must also call into exercise his deductive faculties 

 and employ them to the fullest, if he would make the best progress 

 in the newer phases of his subject, however purely inductive he 

 has imagined it to be. In setting up a store of types, there is need 

 of deducing one type from another at every step ; and it may be 

 confidently urged that whoever hesitates to recognize this princi- 

 ple will fail of his effort to describe through explanation. But as a 



